Centrifuging apparatus



C. C. 5- LE CLAIR CENTRIF'UGING APPARATUS Aug. 22, 1950 2 Sheets-Sheet 2 Filed Nov. 26, 1945 3 that due to the pressure of the liquid at the outlet end of the spill passage, and a spring is used to augment the force due to last mentioned pressure, so that when not in operation the spill valve is maintained in an open position.

In a modified apparatus, however, the relative sizes of the end of the piston within the cylinder and the opposite end or valve face are such that the force due to the pressure of the liquid supplied to the cylinder from the outlet conduit is less than that due to the pressure of the liquid at the outlet end of the spill passage, and a spring is used to augment the force due to the pressure of the liquid in the outlet conduit acting upon the piston, so that the spill valve when not in operation isnormally maintained in a closed position.

Further constructional features of the invention will be described hereinafter.

For a clearer understanding of the invention, a number of constructional-forms of the apparatus will now be described, by way of example, with reference to the accompanying drawings, wherein:

' Figure 1 is a sectional view of a simple construction provided with a single spill passage, without valve control;

Figure 2 is a sectional view of a modification having a single spill passage, with valve control; Figure 3 is a sectional view'of another modification which is provided with two spill passages, both having valve control; and

Figure 4 is a sectional view of a further modification provided with a single valve-controlled spill passage and a modified construction of diaphragm, which is formed with ports to provide access for the liquid from the bowl to the spill passage.

Referring first to Fig. 1:

In the constructional form of the invention shown in Fig. 1, the centrifuging apparatus comprises an outer shell which, for convenience, is made in two parts I and 2, the part I being formed with a short cylindrical part 3 integral with a conical part 4 and the part 2 being formed with a short cylindrical part 5 integral with'a conical part 6. The opposite end of the conical part 6 is formed with a hollow conduit 1 and the opposite end of the other conical part4 is formed with a short cylindrical end Part 8 which surrounds, but is spaced from, another hollow conduit 9. The two cylindrical parts 3 and 5 are formed with circumferential flanges l and II- which are bolted together. The conduit 1 forms the liquid inlet conduit and the other conduit 9 forms the liquid outlet conduit, and the two conduits form one continuous-spindle which is rotatable in two ball bearings l2 and I3 arranged in the walls of a casing l4 which surrounds the apparatus. The apparatus is driven by gearing (not shown) engaging with a pinion [4A on the part 2, liquid-tight seals l and I5 being provided adjacent to the bearings in order to render the casing liquid-tight.

-For convenience, the conical end 6 of the outer shell adjacent to the inlet conduit 1 will be called the inlet cone and the conical end 4 adjacent to the outlet conduit -9 will be called the outlet cone. Within the outer shell is mounted an inner shell, which is formed with similar inlet and outlet'cones Hand 18 connected by a central cylindrical part l9.

In this construction, the inlet cone I! of. the inner shell is connected to the inlet cone 6 of the outer. shell by spaced ribs 20.. The inlet cones l1 and 6, the cylindrical parts l9 and 3 and 5 and the outlet cones l8 and 4 of the two shells are parallel respectively to one another and annular passages 2!, 22 and 23 are formed between the shells, these passages being referred to hereinafter respectively as the inlet passage," the bowl and the outlet passage. 1

The casing I4 not only provides a support for the bearings and protects the apparatus and its driving gear from external dirt, but it also acts to catch the spilled fraction of the liquid and drain it to a sump or container (not shown).

The outlet conduit 9 which, as mentioned above, is surrounded by a short cylindrical end 8 of the outlet cone, is integral with a conical diaphragm 24 which is arranged within the outlet passage and is spaced slightly from the outlet cone 4 of the outer shell I. The outer surface of the diaphragm is parallel to the inner surface of the outlet cone, so that a conical annular passage 25 (hereinafter called a spill passage) of constant width is split off from the outlet passage and'formed between the diaphragmpr skimming cone 24 and outlet cone 4 of the outer shell and between the said cylindrical end 8 of the outer shell and the outlet conduit 8.

In the operation of the apparatus, liquid flows from the pump through the inlet conduit 1, outwards away from the axis of rotation through the inlet passage 2|, through the parallel passage or bowl 22, and then inwards again through the outlet passage 23 to the outlet conduit 9. -At the extreme (radially) outer edge or tip of the diaphragm 24, a small fraction of the liquid is separated from the main stream flowing through the outlet passage and passes'inwards through the spill passage 25- to its spill outlet 25A from which it passes to atmosphere or to the space inside the casing as will be described below.

As this fraction is abstracted from the main flow at the maximum radius of the bowl, it will carry with it all the suspended matter which has been separated out by centrifugal force.

After alparticle of suspended matter has passed the tip-of the diaphragm 24 into the-spill passage 25, it will be carried forwards and constrained to move inwards towards the rotational axis by the forward inward flow of the liquid, but at the same time it will also be constrained to move outwards (i. e., against the flow of the liquid) by centrifugal force. In order that the spill passage may not become clogged, it is necessary that the velocity of inward flow of the liquid shall at any and every point be greater than the velocity of outwardflow-of the particles through the liquid due to centrifugal force at thesamepoint.

The velocity of flow of the particles through the liquid will be a function of the centrifugal force, i. e., when the latter is greater, the velocity willbe greater, and when: less, the velocity will be less. Since centrifugal force is proportional to the radius of rotation,itfollows that' it is greater at the inlet end of the spill passage 25 than it is at the outlet end, where the radius of rotation is less. Hence as. a particle moves through the spill passage. from the inlet to the outlet end it is subjected to progressively decreasing centrifugal force.

On the other hand, the cross sectional area of the spill passageat any radius is the circumference times the width between the inside surface of the outlet cone 4 of the outer shell, and the outside surface .ofwthe diaphragm 24. ,It

5 these surfaces are parallel, so that the' Width is constant throughout the length or the passage, the area will be proportional to the circumfer ence and, as the circumference is proportional to the radius, it follows that'the area at any radiusis proportional to the radius at that point.

Since the velocity of flow of the liquid through the spill passage is inversely proportional to the cross sectional area of the passage it follows that it is also inversely proportional to the radius, hence as a particle moves forward "to positions of less radius it is carried in a liquid moving at increasing velocity. Hence, if the lowest velocity of flow-of the liquid at the tip of the diaphragm 'H (i. e., at the entry to the spill passage 25) "is greater than the greatest velocity of new of the particlesthrough the liquid due to the greatest centrifugal force at the same point, the passage will not become clogged at its'inlet and it follows that the increasing velocity of th'e liquid at all other points in the spill passage will be progressiveiy more than suflic'ient to overcome the decreasing centrifugal force so that clogging will not occur at any other point. This increas, ing velocity will, however, lead to an increasingly steep pressure gradient. 1 v I Since the pressure at the inlet to the spill passage 25- is the line pressure, which, in practice, 'is-of the order 50-60 lbs. per square inch, and as the passage is, iii-practice, only 1 to .2" long in the radially inward direction of flow, it follows that the pressure gradient will have to be very steep and hence, the increasingly steep pressure gradient referred to above may be an ad vantage.

In the case of engines running under constant conditions of speed, working pressure and so on, it will be possible to design the parts of the apparatus so that the quantity of oil spilled is the correct designed amount without further control.

On the other hand, in cases such as automobile or aircraft engines, wherein the engine speed and ioad vary and as a result, the oil main pressure, oil quantity, and centrifugal force all vary and, further, as it may be desirable to vary the amount of oil spilled '(e. g., in proportion to the amount of oil pumped) some form of control of the spill passage outlet will be necessary because, other rise, at times the'discharge may be toogreat "and at others too small.

' This control may conveniently be provided by a spring and/or pressure-loaded valve already referred to as the spill valve.

Referring to Fig. 2, the spill valve comprises a sleeve member 26 forming a hollow annular piston which surrounds and slides upon the outlet conduit '9 andwhich is slidable in a cylinder '1 concentric and integral with or attached to the outlet conduit. Holes are cut through the wall of the outlet conduit in order to provide communication between the latter and the inside or the cylinder '2! and thus communicate the pallet conduit pressure to the back of the piston. opposite end of the sleeve member 26 is formed as a valve face 26A, which is of the same diameter and effective area as theipiston end and which closes against a valve. seat 2 9 formed on the end of the cylindrical end 8 of the outlet cone 4 of the outer shell. The sleeve member is also formed with a flange 30 against which a spring 31 thrusts in a direction to hold the valve The forces imposed upon the sleeve member a are the outlet conduit pressure in) upon the piston end of the sleeve member urging the valve 6 2m shut and the spilling pressure (13.) upon the valve end of the sleeve member urging the valve open.

Since the areas of the piston end and the valve face end 01' the sleeve are equal, and since the spilling pressure is less than the outlet conduit pressure (due to the pressure gradient in the spill passage 25) the force (B) urging the valve open is less than the force (A) urging it shut.

To maintain equilibrium, therefore, it is necessary to add the thrust ((3) of the aforesaid spring 31- in a direction acting to open the valve such that:

Since under working conditions, the spring load (C) is. constant and the areas of the p'iston'and valve ends are equal it follows that the difference between the spilling pressure and outlet conduit pressure must be constant, 1. e., the pressure drop through the spilling passage 25 is constant and hence the quantity of liquid spilled will be constant more or less irrespective of the total amount circulated.

Moreover. since the spring load is adjustable, the pressure drop and hence the spilled quantity of liquid is also adjustable to a predetermined amount.

As previously explained, however, it may be desirable that the spilled quantity should not be kept constant but should vary, e. g.. in proportion to the total quantity of liquid delivered. Such variations can be obtained by varying the ratio of the piston area to the valve face area of the said sleeve member '26 and possibly also by varying the characteristic of the spring.

In some cases, see Fig. 3, for example, the piston area may be made so much smaller than the valve face area that the force (A) urging the valve shut is less than the force (B) urging .it open so that A-B is negative and it becomes necessary to mount the spring in such a manner that its thrust urges the valve shut instead of urging it open.

In this construction, the piston is in the form of a sleeve member 2613 which is formed with a circumferential flange 33 at its end adjacentto the outlet of the spill passage 25 and the flange is formed with a projecting-annular valve part '34 which is adapted to cooperate with the end 29A of the cylindrical end 8 of the outlet cone l of the outer shell I. The area of the valve face end of the sleeve member is thus relatively much greater than that of the piston end.

In any of these constructions, whether the spring acts to thrust the valve open or shut, may be desirable to provide means for adjusting its initial load. This can be done as shown in Fig. 3, by cutting an external thread 35 upon the cylinder 27A in which the sleeve member 26B is slidable and screwing an adjustable ring '36 on to this thread. The coil spring 31A is then arranged between the adjustable ring 36 and the flange 33 on the sleeve member and acts to urge the valve shut. By screwing the adjusting ring 36 backwards or forwards, the pressure of the spring 31A upon the sleeve member 263 can be varied.-

In all or any of these cases, owing to the resistanoe offered by the spill valve it may be desirable to keep down the steepness of the pressure gradient through the spill passage so as to permit a pressure considerably higher than atmospheric to exist at a point (for example, the point in vFigs. v.2 and 3) .just adjacent to the spill valve within the outer shell. This can be done by in- ..creasing the width of the spill passage at the outlet end, for example, by formingthe diaphragm to a steeper angle than the outlet cone of the outer shell, such a construction being shown in Fig. 2. The width of the inlet end of the spill passage at the tip of thediaphragm is then less than at the outlet end of the passage surrounding the outlet conduit.

By suitably designing the apparatus, the-velocity, and hence the pressure gradient, may be completely controlled e. g., the velocity may be kept constant or it maybe designed to fall proportionally with the centrifugal force, thus giving a much lower pressure gradient. It must be borne in mind, however, that the velocity of flow of the liquid at any point must never be allowed to fall below the velocity of flow of the particles through the liquid due to centrifugal force at the same point.

In a modified construction of the apparatus shown in Fig. 4, the conical diaphragm 230 is provided with a cylindrical part 31 which is parallel to the central cylindrical portion 3 of the outer shell and is provided with a circumferential flange 38 which is fitted between, and is' bolted to, the flanges I and II on the outer and inner shells. A number of holes or slots 39 are cut through the cylindrical part 3'! of the diaphragm to provide egress for the liquid fraction carrying the solid matter to be spilled through the spill passage 253. In this construction also, the width of the spill passage may be constant or it may be made variable. Shims 40 may be introduced into the flange joint between the two parts of the outer shell in order to vary the width of the passage. The same construction may be used with any of the valve arrangements previously described.

Referring again to Fig. 3. This shows a double ended embodiment having two spill passages. The diaphragm 23B is arranged on the outlet side of the apparatus being integral with the outlet duct 9, and splitting off a spill passage from the outlet passage, all as previously described in connection with Fig. 2. Similarly the diaphragm 23D is arranged in the inlet side of the apparatus being integral with the inlet duct 1 and splitting off a spill passage from the inlet passage 2 M. The tips or inner edges of the diaphragms are :spaced apart in the bowl part of the outer shell, two spill passages thus being provided at opposite ends of the apparatus. The outlet end of each of these spill passages may be controlled by a spill valve arrangement constructed in any of the ways referred to above. f

Slipping and free wheel clutches (e. g., of the type mentioned in Patent No. 2,476,377 issued July 19, 1949, to Camille Clare Sprankling Le Clair) may be incorporated in the mechanism for driving the apparatus in cases in which the driving means is subject to quick acceleration and deceleration.

I claim:

1. centrifuging apparatus for centrifuging liquid under pressure comprising in combination a rotatable outer shell, an inner shell arranged within said outer shell and rotatable therewithand spaced therefrom so as to form with said outer shell a continuous annular passage, said annular passage including an annular inlet passage through which liquid to be centrifuged flows under pressure outwardly away from the rotational axis of the apparatus, an annular outlet passage, and an intermediate annular bowl passage interconnecting the adjacent extremities of said inlet and outlet passages, and extending substantially parallel to the axis of rotation of. said shells and meansin said continuous annular pas; sage rotatable with and spaced from said outer shell so as to define in said continuous passage between said outer shell and said means an annue lar spill passage, said spill passage having its inlet adjacent to said intermediate annular bowl passage and its outlet arranged nearer to said axis than its inlet, so that liquid which enters said spill passage from said intermediate annular bowl passage will flow inwardly through said spill passage towards said axis while the bulk of the centrifuged liquid is discharged under pres sure through said outlet passage.

2. Centrifuging apparatus for centrifuging liquid under pressure comprising in combination arotatable outer shell, an inner shell arranged within said outer shell and rotatable therewith and spaced therefrom so as to form with said outer shell a continuous annular passage, said annular passage including an annular inlet passage through which liquid to be centrifuged flows under pressure outwardly away from the rotational axis of the apparatus, an annular outlet passage through which liquid flows inwardly toward said axis, and an intermediate annular bowl passage interconnecting the adjacent outer extremities of said inlet and outlet passagesand extending substantially parallel to the axis of rotation of said shells, and means in said annular outlet passage rotatable with and spaced from said outer shell so'as to define in said outlet passage between said outer shell and said means an annular spill passage, said annular spill passage having its inlet adjacent to said intermediate annular bowl passage whereby of the quantityoi liquid supplied uncer pressure to the apparatus a fraction containing suspended material is forced to enter said spill passage from said bowl passage and to flow inwardly through said spill passage toward said axis for discharge from the outlet of said spill passage while the bulk'of the centrifuged liquid is discharged under pressure through said outlet passage, an inlet conduit communicating with said inlet passage, and an outlet conduit communicating with said outlet passage, said inlet and outlet conduits being coaxial and forming a hollow shaft upon which the apparatus rotates. 1

3. centrifuging apparatus for centrifuging liquid under pressure comprising in combination a rotatable outer shell, an inner shell arranged within said outer shell and rotatable therewith and spaced therefrom so as to :form with said outer shell a continuous annular passage, said annular passage including an annular inlet passage through which liquid to be centrifuged flows under pressure outwardly away from the rotational axis of the apparatus, an annular outlet passage through which liquid flows inwardly toward said axis, and a laterally extending intermediate annular bowl passage interconnecting the adjacent outer extremities of said inlet and outlet passages, and means in said annular inlet passage rotatable with and spaced from said outer shell so as to define in said inlet passage between said outer shell and said means an annular spill passage, said annular spill passage having its inlet adjacent to said intermediate annular bowl passage and its outlet arranged nearer to said axis than its inlet, whereby of the quantity of liquid supplied under pressure to the apparatus a fraction containing suspended material is forced to enter said spillpassage from said bowl passage and to flow inwardly through said spill passage toward said axis and is discharged from said :spiinoutlet, -;an'=.1n1et nendu'it communicating with said inlet passage, and an outlet conduit communicating with said out-v let-passage, said inlet and outlet conduits ;being coaxial and forming a hollow sharia upon which the'apparatus rotates.

1 Centrifuging apparatus :lior centrifuging li'q'uid under pressure comprising in'combination a rotatable outer shell, an inner :shell :arranged within said outer shell and rotatable therewith and spaced therefrom so as to form with :said cuter shell a continuous annular passage, *said annular passage including an annular inlet'spassage through whichliquidito bez-centriiuged lflows under pressure outwardly away from the rotational axis of the apparatus, an annular outlet passage through which liquid flows inwardly toward said axis, and an intermediate annular bowl passage connecting the adjacent outer extremities of said inlet and outlet passages, and means in said annular inlet passage and similar income in said annular outlet "passage rotatable with :and spaced from said outer shell .so "as to define with said outer-shell a pair of *a'nnular spill passages, said annular spill passa'ges having their inlets adj acent to said intermediate annular bowl passage and their outlets arrangednearer to said axis than their inlets, whereby of the quantity of liquid supplied under pressure to the apparatus a fraction containing suspended material is forced to enter said spill passages from said bowl passage and to flow "inwardly through said spill passages toward said ''axis midisiliecharged "from said spill outletsp-an inlet conduit communicating with said inlet passage, and an outlet conduit communicating with said outlet passage, said inlet and outlet conduits being co axial and forming a hollow shaft upon which the apparatus rotates.

5. centrifuging apparatus for centrifuging liquid under pressure comprising in combination a rotatable outer shell having a pair of conical portions connected by a generally cylindrical portion, an inner shell arranged within said outer shell and rotatable therewith and having a pair of conical portions connected by a generally cylindrical portion, said inner shell being spaced from said outer shell and forming therewith a continuous annular passage including an annular inlet passage through which liquid to be centrifuged flows under pressure outwardly away from the rotational axis of the apparatus, an annular outlet passage through which liquid flows inwardly toward said axis, and an intermediate annular bowl passage formed between said generally cylindical shell parts and interconnecting the adjacent outer extremities of said inlet and outlet passages and extending substantially parallel to the axis of rotation of said shells, an inlet conduit communicating with said inlet passage, an outlet conduit communicating with said outlet passage, said inlet and outlet conduits being coaxial and forming a hollow shaft upon which the apparatus rotates, and means in said continuous annular passage rotatable with and spaced from said outer shell so as to define in said continuous passage between said outer shell and said means an annular spill passage, said spill passage having its inlet adjacent to said intermediate annular bowl passage and its outlet nearer to sad axis than its inlet, so that liquid which enters said spill passage from said intermediate annular bowl passage will flow inwardly through said spill passage toward said axis while the bulk of the cen- 10 trifuged liquid is discharged under pressure through said outlet passage and "conduit.

"6. Centrifug'ing apparatus aclaimed in 'claim "'5 wherein said means is "a "skimming :cone' arranged within said outlet passage and is :ror'med integral with :said outlet conduit.

7. "centrifuging apparatus -'as claimed in claim li'whereinsa idmeans is a conical diaphragm arranged within said outlet passage an'd'is'fori'ned integral with said out'le't conduit, said diaphragm being provided at its inner edge witha cylindrical part which is spaced from said cylindrical art o'f'saidouter shell so as to forman annular part of said 'spill passage, and a plurality of spaced slots in said cylindrical diaphragm part bon necting said annular bowl passage with said annular part of said spill passage.

"8. :Centrifug'ing apparatus as claimed in claim 5 wherein said means is spaced equidistantly "from said outer shell through the length "of "said :spill passage.

9. centrifuging apparatus as claimed "in claim 5 wherein said means is so spaced from said outer shell that the width of said s ill passage varies from sa'id'spill inlet to said spill outlet.

. 10. centrifuging apparatus for centrifuging "liquid under pressure comprising in combination aro'tatable outer shell, an inner shell arranged within said outer shell and rotatable therewith and "spaced therefrom so as to form with said outer shell a continuous annular passage, said continuous annular passage including an annular lin'le't passage through which liquid to be centrifuged flows under pressure outwardly -away from the rotational axis of the apparatus'ari annular outlet passage through which liquid flows inwardly toward said axis, and an intermediate annular bowl passage connecting the adjacent outer extremities of said inlet and outlet passages and extending substantially parallel to the axis of rotation of said shells, an inlet conduit communicating with said inlet passage, an outlet conduit communicating with said outlet passage, said inlet and outlet conduits being coaxial and forming a hollow shaft upon which the apparatus rotates, skimming means in said continuous annular passage rotatable with and spaced from said outer shell so as to define in said continuous passage between said outer shell and said means an annular spill passage, said spill passage having its inlet adjacent to said intermediate annular bowl passage and its outlet nearer to said axis than its inlet, so that liquid which enters said spill passage from said intermediate annular bowl passage will flow inwardly through said spill passage toward said axis while the bulk of the liquid is discharged under pressure through said outlet passage and conduit, and means for controlling the flow of liquid from said spill passage outlet.

11. centrifuging apparatus as claimed in claim 10 wherein said flow controlling means comprises a pressure operated valve.

12. Centrifuging apparatus as claimed in claim 10 wherein said flow controlling means comprises a spring operated valve.

13. centrifuging apparatus as claimed in claim 10 wherein said flow controlling means comprises a valve, and including means connecting said valve so that it is biased in the closed direction by the pressure of the liquid in the outlet conduit whereby said valve is opened by the pressure of the liquid in said spill passage.

14. centrifuging apparatus as claimed in claim wherein said flow controlling means comprises a valve cooperating with a valve seat surrounding said spill passage outlet-said valve being formed on a piston slidably mounted upon saidhollow shaft and within a cylinder coaxial with said shaft, means communicating the interior of said cylinder with the interior of said hollow shaft to utilize the pressure of the liquid in said shaft to bias said piston and valve toward closed position, said piston and valve being moved toward open position by the pressure of the liquid in said spill passage.

7 15. centrifuging apparatus as claimed in claim 10 wherein said flow controlling means comprises a valve, and including a spring to operate said valve, and means for varying the loading of said spring.

16. centrifuging apparatus as claimed in claim 10 wherein said flow controlling means comprises a valve cooperating with a valve seat surrounding said spill passage outlet, said valve being formed'on one face of a piston slidably mounted upon said outlet conduit and within a cylinder, means communicating the interior of said cylinder with said conduit, the relative areas of said valve face and the piston head within said cylinder being such that the pressure supplied to'said piston head from said outlet conduit is greater than that due to the pressure of the liquid at the outlet end of said spill passage, and spring means augmenting the force of the last mentioned pressure to maintain said valve in open position.

17. centrifuging apparatus as claimed in claim .10 wherein said flow controlling means comprises a valve cooperating with a valve seat surrounding said spill passage outlet, said valve being formed on one face of a piston slidably mounted upon said outlet conduit and within a cylinder, means communicating the interior of said cylinder with said conduit, the relative areas of said valve face and the piston head within said cylinder being such that the. pressure supplied to said piston head from said outlet conduit is less than that due to the pressure of the liquid at the outlet end of said spill passage, and spring means augmenting the force due to the pressure from said outlet conduit to maintain said valve in closed position.

CAMILLE CLARE SPRANKLING LE CLAIR.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 165,785 Braun July 20, 1875 937,986 Carlsson Oct. 26, 1909 1,052,777 Ward et a1. Feb. 11, 1913 1,056,233 Trent Mar. 18, 1913 1,101,548 Hoffman June 30, 1914 2,177,082 Staafl Oct. 24, 1939 FOREIGN PATENTS Number Country Date 17,250 Great Britain Aug. 25, 1905 302,685 Great Britain Dec. 12, 1928 392,411 France Sept. 24, 1908 663,261

France Apr. 8, 1929 

